Try this,
NSString *string = self.textView.text;
__block NSString *deleteWord = nil;
__block NSRange rangeOfWord;
[string enumerateSubstringsInRange:NSMakeRange(0, self.textView.selectedRange.location + self.textView.selectedRange.length) options:NSStringEnumerationByWords | NSStringEnumerationReverse usingBlock:^(NSString *substring, NSRange subrange, NSRange enclosingRange, BOOL *stop) {
deleteWord = substring;
rangeOfWord = enclosingRange;
*stop = YES;
}];
if ([emoticons containsObject:deleteWord]) {
string = [string stringByReplacingCharactersInRange:rangeOfWord withString:@""];
self.textView.text = string;
self.textView.selectedRange = NSMakeRange(rangeOfWord.location, 0);
}